The ability to construct increasingly small structures is of great importance in the fabrication of advanced electronic and optical electronic devices. Particularly, the construction of well defined devices having structures of less than 100 nanometers in size has been widely sought. Various attempts have been made to construct such devices. Techniques employed have included electronic-beam lithography. See P. Rai-Choudhury, Ed. SPIE handbook of microlithography, micromachining and microfabrication (SPIE, 1997) vol. 1. Other techniques have used a scanning probe microscope (SPM). See H. Sugimura, N. Nakagiri, J. Am. Chem. Soc. 119, 9226 (1997); M. A. Reed, J. Chen, C. L. Asplund, A. M. Cassell, M. L. Myrick, A. M. Rawlett, J. M. Tour, P. G. Van Patten, Appl. Phys. Lett. 75, 624 (1999); S. Hong, J. Zhu, C. A. Mirkin, Science 286, 523 (1999). Another technique is quantum dot (QD) deposition. See Y. Golan, L. Margulos, G. Hodes, I. Rubinstein, J. L. Hutchison, Surf. Sci. 311, 633 (1994). Yet another technique is nanotube assembly. See S. J. Tans, A. R. M. Verschueren, C. Dekker, Nature 393, 49 (1998); E. W. Wong, P. E. Sheehan, C. M. Lieber, Science 277, 1971 (1997); T. W. Ebbesen, H. J. Lezec, H. Hiura, J. W. Bennett, H. F. Ghaemi, T. Thio, Nature 382, 54 (1996); rod assembly; B. R. Martin, D. J. Dermody, B. D. Reiss, M. Fang, L. A. Lyon, M. J. Natan, T. E. Mallouk, Adv. Mater. 11, 1021 (1999). Yet another technique is membrane tubes deposition. See E. Evans, H. Bowman, A. Leung, D. Needham, D. Tirrell, Science 273, 933 (1996). Another technique is metal-coated DNA. See E. Braun, Y. Eichen, U. Sivan, g. Ben-Yoseph, Nature 391, 775 (1998). Despite all these different possible methods of creating nanostructures, problems and limitations remain.
For example, electronic beam lithography is often limited in its resolution below 100 nm due to proximity effects that may cause broadening of the desired pattern. See Y. Wang, S. Y. Chou, J. Vac. Sci. Technol. B 10, 2962 (1992). When portions of a pattern broaden, the result can be the merging or blurring of two adjacent structures. This is, of course, undesirable as it produces a structure different from that intended.
Using a scanning probe microscope for fabrication also has problems. One problem with this method is that it requires assembly of nanostructures one at a time. This resource intensive method limits the ability to construct an array that can span a macroscopic area.
There are also problems with using quantum dot deposition. Quantum dot deposition of small nanostructures results in heterogeneous distributions of structures, and the spacings between the dots cannot be precisely and broadly controlled. Therefore, the creation of precise nanostructures is problematic.
Methods involving nanotubes, membrane tubes, and rods are limited to predetermined widths and properties, and their ordered alignment on surfaces requires special techniques. These limitations make these techniques inappropriate for the creation of nanostructures for electronic devices.
In electronic circuit fabrication, using resists is known. Resists, however, are currently made of polymer and are spin-coated to make a nominally uniform layer on the substrates. Therefore, these resists are not selectively adsorbed to patterned areas on the surface, and do not yield precisely defined spacings, making them unsuitable for narrowing the gap between extremely small neighboring nanostructures in electronic devices.
In addition, monolayers have been proposed as resists, but defects in the monolayers tend to render these monolayer resists as not viable for use in constructing nanostructures.
As can be seen from the foregoing discussion, creating devices with nanoscale structures remains a considerable problem. Thus, a need exists in the art for a method of creating nanostructures that is capable of use in electronic component fabrication and in creating precisely spaced structures.
It is therefore an object of the present invention to provide a method for creating nanostructures that greatly improves over the state of the art.
It is another object of the present invention to provide a method of creating nanoscale structures that results in structures that are precise.
It is a further object of the present invention to provide a method for creating nanoscale structures that can be used to create structures less than 100 nm in width.
It is a further object of the present invention to provide a method for creating nanoscale structures that provides for precise spacing between nanoscale structures.
It is a further object of the present invention to provide a method for making nanoscale structures that permits complex patterns to be made.
It is a further object of the present invention to provide a method for making a nanoscale structures that permits a variety of structures to be created.
It is a further object of the present invention to provide a method of creating nanostructures that allows a number of different nanostructures to be constructed in a single fabrication process or in a series of simple steps.
It is a further object of the present invention to provide a method to reduce the size of fabricated structures.
Other objects of the invention will become apparent from the description of the invention and that which follows.